Configuring Custom Domain in Azure B2C Using Application Gateway

Question

Is it possible to configure a custom domain in Azure B2C using an Application Gateway instead of Azure Front Door? What specific guidelines or considerations should be kept in mind for this approach?

Answer 1

@Gerald Ortiz Candela ,

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I believe you are referring to Enable custom domains in Azure Active Directory B2C

• I don't see any official recommendations from Azure documentation highlighting the use of App Gateway
• While App Gateway is also a reverse proxy, you must note that App Gateway is a regional resource while AFD and AAD (Entra ID) are distributed globally.
• This means users from different regions than the App Gateway will experience a higher latency than compared to users who access the Entra login directly or via AFD.

While this is technically achievable, I recommend you not to use App Gateway.

If you would like to use App gateway still,

• As there are no documentations available, you have to do a test configuration in a lower/dev environment
• Make sure you follow all the recommendations in Hostname preservation and review it's Potential problems
  • Also see : Implementation guidance for common Azure services behind Reverse Proxy
• You can follow the same steps in AFD Documentation, and configure
  • DNS to point to the App gateway's Public IP
  • App gateway's backend configuration as mentioned here
  • And add the custom domain to the AAD B2C as mentioned here

Once again, as this is not a documented set up, please make sure you try this in a lower/dev/test environment.

Kindly let us know if this helps or you need further assistance on this issue.

Thanks,

Kapil

---

Please don’t forget to close the thread by clicking "Accept the answer" wherever the information provided helps you, as this can be beneficial to other community members.